U.S. patent application number 17/078948 was filed with the patent office on 2021-02-11 for image sensor device.
This patent application is currently assigned to TAIWAN SEMICONDUCTOR MANUFACTURING CO., LTD.. The applicant listed for this patent is TAIWAN SEMICONDUCTOR MANUFACTURING CO., LTD.. Invention is credited to Shiu-Ko JANGJIAN, Chun-Che LIN, Yu-Ku LIN, Chih-Nan WU.
Application Number | 20210043670 17/078948 |
Document ID | / |
Family ID | 1000005170234 |
Filed Date | 2021-02-11 |
United States Patent
Application |
20210043670 |
Kind Code |
A1 |
JANGJIAN; Shiu-Ko ; et
al. |
February 11, 2021 |
IMAGE SENSOR DEVICE
Abstract
An image sensor device includes a semiconductor device, a
plurality of photo sensitive regions, a dielectric layer, a grid
structure, and a plurality of convex dielectric lenses. The
plurality of photo sensitive regions are in the semiconductor
substrate. The dielectric layer is on a backside surface of the
semiconductor substrate facing away from the plurality of photo
sensitive regions. The grid structure is on a backside surface of
the dielectric layer facing away from the semiconductor substrate.
The grid structure includes a plurality of grid lines spaced from
each other. The plurality of convex dielectric lenses are
alternately arranged with the plurality of grid lines of the grid
structure on the backside surface of the dielectric layer. Apexes
of the plurality of convex dielectric lenses are lower than top
ends of the plurality of grid lines of the grid structure.
Inventors: |
JANGJIAN; Shiu-Ko; (Tainan
City, TW) ; WU; Chih-Nan; (Tainan City, TW) ;
LIN; Chun-Che; (Tainan City, TW) ; LIN; Yu-Ku;
(Tainan City, TW) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
TAIWAN SEMICONDUCTOR MANUFACTURING CO., LTD. |
Hsinchu |
|
TW |
|
|
Assignee: |
TAIWAN SEMICONDUCTOR MANUFACTURING
CO., LTD.
Hsinchu
TW
|
Family ID: |
1000005170234 |
Appl. No.: |
17/078948 |
Filed: |
October 23, 2020 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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16525372 |
Jul 29, 2019 |
10818716 |
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17078948 |
|
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|
14109318 |
Dec 17, 2013 |
10367021 |
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16525372 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01L 27/14645 20130101;
H01L 27/14685 20130101; H01L 27/14621 20130101; H01L 27/14627
20130101; H01L 27/1463 20130101 |
International
Class: |
H01L 27/146 20060101
H01L027/146 |
Claims
1. An image sensor device, comprising: a semiconductor substrate; a
plurality of photo sensitive regions in the semiconductor
substrate; a dielectric layer on a backside surface of the
semiconductor substrate facing away from the plurality of photo
sensitive regions; a grid structure on a backside surface of the
dielectric layer facing away from the semiconductor substrate, the
grid structure comprising a plurality of grid lines spaced from
each other; and a plurality of convex dielectric lenses alternately
arranged with the plurality of grid lines of the grid structure on
the backside surface of the dielectric layer, apexes of the
plurality of convex dielectric lenses being lower than top ends of
the plurality of grid lines of the grid structure.
2. The image sensor device of claim 1, wherein each of the
plurality of convex dielectric lenses has a refractive index lower
than a refractive index of the dielectric layer.
3. The image sensor device of claim 1, wherein each of the
plurality of grid lines comprises a lower portion and an upper
portion over the lower portion, and the lower portion is made of a
different material than the upper portion.
4. The image sensor device of claim 3, wherein the lower portion of
each of the plurality of grid lines has a refractive index lower
than a refractive index of the dielectric layer.
5. The image sensor device of claim 3, wherein the lower portion
and the upper portion of one of the plurality of grid lines form an
interface level with the apexes of the plurality of convex
dielectric lenses.
6. The image sensor device of claim 3, wherein the lower portion
and the upper portion of one of the plurality of grid lines form an
interface lower than the apexes of the plurality of convex
dielectric lenses.
7. The image sensor device of claim 3, wherein the lower portion of
each of the plurality of grid lines has a refractive index higher
than a refractive index of each of the plurality of convex
dielectric lenses.
8. The image sensor device of claim 1, further comprising: a
dielectric structure in contact with the apexes of the plurality of
convex dielectric lenses, the dielectric structure having a
refractive index lower than a refractive index of each of the
plurality of convex dielectric lenses.
9. The image sensor device of claim 8, wherein the dielectric
structure is further in contact with an entirety of a sidewall of
each of the plurality of grid lines.
10. The image sensor device of claim 9, wherein the dielectric
structure is further in contact with an entirety of the top end of
each of the plurality of grid lines.
11. The image sensor device of claim 8, wherein the dielectric
structure is in contact with an entirety of a convex surface of
each of the convex dielectric lenses.
12. An image sensor device, comprising: a semiconductor substrate;
a plurality of photo sensitive regions in the semiconductor
substrate; a first dielectric layer on a backside surface of the
semiconductor substrate facing away from the plurality of photo
sensitive regions; a plurality of convex dielectric lenses on a
backside surface of the first dielectric layer facing away from the
semiconductor substrate; a dielectric structure over convex sides
of the plurality of convex dielectric lenses; a layer of color
filters on a backside surface of the dielectric structure facing
away from the plurality of convex dielectric lenses; and a
plurality of micro-lenses on a backside surface of the layer of
color filters facing away from the dielectric structure, wherein
the plurality of micro-lenses respectively overlap the plurality of
convex dielectric lenses, and each of the plurality of micro-lenses
laterally extends past opposite edges of a corresponding one of the
plurality of convex dielectric lenses.
13. The image sensor device of claim 12, further comprising: a
patterned second dielectric layer on the backside surface of the
first dielectric layer, the patterned second dielectric layer
having a plurality of portions alternately arranged with plurality
of convex dielectric lenses.
14. The image sensor device of claim 13, wherein the patterned
second dielectric layer has a refractive index lower than a
refractive index of the first dielectric layer.
15. The image sensor device of claim 13, further comprising: a grid
disposed on the patterned second dielectric layer.
16. The image sensor device of claim 12, wherein each of the
plurality of convex dielectric lenses has a refractive index lower
than a refractive index of the first dielectric layer.
17. An image sensor device, comprising: a semiconductor substrate;
a plurality of photo sensitive regions in the semiconductor
substrate; a layer of a first dielectric material on a backside
surface of the semiconductor substrate farthest from the plurality
of photo sensitive regions; a plurality of convex dielectric lenses
on a backside surface of the layer of the first dielectric material
farthest from the semiconductor substrate; a lower grid structure
on the backside surface of the layer of the first dielectric
material, the lower grid structure comprising a plurality of lower
grid lines alternately arranged with the plurality of convex
dielectric lenses from a cross-sectional view, the plurality of
lower grid lines being formed of a second dielectric material
having a lower refractive index than the first dielectric material;
and an upper grid structure having a plurality of upper grid lines
respectively over the plurality of lower grid lines of the lower
grid structure from the cross-sectional view.
18. The image sensor device of claim 17, wherein each of the
plurality of convex dielectric lenses has a lower refractive index
than the second dielectric material.
19. The image sensor device of claim 17, further comprising: a
dielectric structure wrapping around each of the plurality of upper
grid lines and the plurality of lower grid lines.
20. The image sensor device of claim 19, wherein the dielectric
structure has a lower refractive index than the second dielectric
material.
Description
PRIORITY CLAIM AND CROSS-REFERENCE
[0001] The present application is a continuation application of
U.S. patent application Ser. No. 16/525,372, filed Jul. 29, 2019,
now U.S. Pat. No. 10,818,716, issued Oct. 27, 2020, which is a
continuation application of U.S. patent application Ser. No.
14/109,318, filed Dec. 17, 2013, now U.S. Pat. No. 10,367,021,
issued Jul. 30, 2019, all of which are herein incorporated by
reference in their entireties.
BACKGROUND
[0002] Image sensor devices are widely used in various imaging
applications and products, such as smart phones, digital cameras,
scanners, etc. Typically, an image sensor device uses micro-lenses
to condense incident light into color filters when the incident
light first enters the image sensor device. However, various
dielectric films used in the image sensor device with CMOS
technology increase the number of optical paths, and such films are
transparent to visible light. Even if the image sensor device
includes a grid to block the optical paths from crossing subpixels,
the incident light may dissipate (e.g. penetrate into other pixels
under the grid), in which a crosstalk issue arises, resulting in
signal-to-noise ratio (SNR) degradation.
BRIEF DESCRIPTION OF THE DRAWINGS
[0003] The invention can be more fully understood by reading the
following detailed description of the embodiment, with reference
made to the accompanying drawings as follows:
[0004] FIG. 1 illustrates a schematic cross-sectional diagram of an
image sensor device in accordance with some embodiments of the
present disclosure;
[0005] FIGS. 2A-2B illustrate schematic enlarged partial views of
the image sensor device in FIG. 1 in accordance with various
embodiments;
[0006] FIGS. 3A-3H illustrate schematic cross-sectional diagrams of
intermediate stages in accordance with a method for fabricating an
image sensor device in some embodiments of the present disclosure;
and
[0007] FIG. 4 illustrates a flow chart of a method for fabricating
an image sensor device in accordance with some embodiments of the
present disclosure.
DETAILED DESCRIPTION
[0008] The making and using of the present embodiments are
discussed in detail below. It should be appreciated, however, that
the present disclosure provides many applicable concepts that can
be embodied in a wide variety of specific contexts. The specific
embodiments discussed are merely illustrative of specific ways to
make and use the disclosed subject matter, and do not limit the
scope of the different embodiments.
[0009] Terms used herein are only used to describe the specific
embodiments, which are not used to limit the claims appended
herewith. For example, unless limited otherwise, the term "one" or
"the" of the single form may also represent the plural form. The
terms such as "first" and "second" are used for describing various
devices, areas and layers, etc., though such terms are only used
for distinguishing one device, one area or one layer from another
device, another area or another layer. Therefore, the first area
can also be referred to as the second area without departing from
the spirit of the claimed subject matter, and the others are
deduced by analogy. Moreover, space orientation terms such as
"under", "on", "up", "down", etc. are used to describe a
relationship between a device or a characteristic and another
device or another characteristic in the drawing. It should be noted
that the space orientation term can cover different orientations of
the device besides the orientation of the device illustrated in the
drawing. For example, if the device in the drawing is turned over,
the device located "under" or "below" the other devices or
characteristics is reoriented to be located "on" or "above" the
other devices or characteristics. Therefore, the space orientation
term "on" may include two orientations of "above" and "below".
[0010] Embodiments of the present disclosure are directed to
providing an image sensor device for better photo sensing quality.
In each pixel region of the image sensor device, a convex
dielectric lens is formed between a color filter and a substrate
for condensing incident light into a photo sensitive element, such
that quantum efficiency is improved and a crosstalk issue is
avoided for high signal-to-noise (SNR) ratio, thereby improving the
photo sensing quality.
[0011] Referring to FIG. 1, FIG. 1 illustrates a schematic
cross-sectional diagram of an image sensor device 100 in accordance
with some embodiments of the present disclosure. In the present
disclosure, the image sensor device 100 is a backside illuminated
(BSI) image sensor device. The image sensor device 100 includes
pixel regions 100R, 100G and 100B for converting incident light
into RGB image data. It is noted that the sequence of the pixel
regions 100R, 100G and 100B shown in FIG. 1 is shown as an example
for explanation, and embodiments of the preset disclosure are not
limited thereto.
[0012] In FIG. 1, the image sensor device 100 includes a substrate
110, photo sensitive elements 120R/120G/120B, pixel circuits
122R/122G/122B, a first dielectric structure 130, convex dielectric
lenses 140, a grid 150, a second dielectric structure 160, color
filters 170R/170G/170B and micro-lenses 180. The substrate 110 is a
semiconductor substrate, which includes, but not limited to, a
semiconductor wafer, a silicon-on-insulator (SOI) substrate, an
epitaxial substrate. In some embodiments, the substrate 110 further
includes an elementary semiconductor such as silicon, germanium and
diamond. In another embodiments, the substrate 100 further includes
a compound semiconductor, such as silicon carbide, gallium arsenic,
gallium carbide, gallium phosphide, indium arsenide and indium
phosphide, or an alloy semiconductor, such as silicon germanium,
silicon germanium carbide, gallium arsenic phosphide and gallium
indium phosphide.
[0013] The substrate 110 has a front side 110A and a back side
110B. The photo sensitive elements 120R/120G/120B are formed on the
front side 110A of the substrate 110. The photo sensitive elements
120R/120G/120B are configured to receive the incident light
transmitted from the back side 110B through the substrate 110, and
then to convert the incident light to RGB image data. In some
embodiments, the photo sensitive element 120R/120G/120B are
photodiodes, pinned photodiodes, partially pinned photodiodes,
photogates or photo transistors.
[0014] The pixel circuits 122R/122G/122B are formed on the front
side 110A of the substrate 110 and adjacent the photo sensitive
elements 120R/120G/120B respectively for electrical interconnecting
with the photo sensitive elements 120R/120G/120B, so as to transfer
electric charges generated from the photo sensitive elements
120R/120G/120B. For illustration, each of the pixel circuits
122R/122G/122B includes a reset transistor, a source follower
transfer, a row select transistor and a transfer transistor.
[0015] The first dielectric structure 130 is formed on the back
side 110B of the substrate 110. In FIG. 1, the first dielectric
structure 130 includes a first dielectric layer 132 and a second
dielectric layer 134. The first dielectric layer 132 is formed on
the back side 110B of the substrate 110, and the second dielectric
layer 134 is formed on the first dielectric layer 132. The first
dielectric layer 132 and the second dielectric layer 134 may
include a transparent material, such as silicon oxide, silicon
nitride, combinations thereof, or the like. In some embodiments,
that the material forming the first dielectric layer 132 is
selected to have a refractive index greater than that of the second
dielectric layer 134.
[0016] In each of the pixel regions 100R/100G/100B, the convex
dielectric lens 140 is formed in the first dielectric structure
130. As shown in FIG. 1, the second dielectric layer 134 includes
recesses for forming the convex dielectric lenses 140 therein. At
least one portion of each of the convex dielectric lenses 140 is
located in the second dielectric layer 134. In other words, a
height of each of the convex dielectric lenses 140 may be greater
than, equal to or smaller than a depth of each of the recesses.
Each of the convex dielectric lenses 140 has a refractive index
lower than that of the second dielectric layer 134. Each of the
convex dielectric lenses 140 has a convex side 140A and a planar
side 140B. The convex side 140A is oriented toward the incident
light, whereas the planar side 140B is directly on the recess 136
and oriented toward the photo sensitive element 120R/120G/120B.
[0017] In some embodiments, the first dielectric structure 130 is a
single layer structure. The first dielectric structure 130 may
include a transparent material, such as silicon oxide, silicon
nitride, combinations thereof, or the like. The first dielectric
structure 130 has a refractive index greater than that of each of
the convex dielectric lenses 140.
[0018] The grid 150 is formed on the first dielectric structure
130. The grid 150 separates the pixel regions 100R/100G/100B for
preventing the incident light from passing therethrough. In some
embodiments, the grid 150 includes an insulating material such as
silicon oxide, silicon nitride, silicon oxynitride, combinations
thereof, or the like. In some embodiments, the grid 150 includes a
metal material such as aluminum, copper, or the like, a metal alloy
material such as aluminum alloy, copper alloy, or the like, a metal
nitride such as titanium nitride, tantalum nitride, or other
suitable material.
[0019] The second dielectric structure 160 is formed on the first
dielectric structure 130, the convex dielectric lenses 140 and the
grid 150. The second dielectric layer 160 may include a transparent
material, such as silicon oxide, silicon nitride, combinations
thereof, or the like. The material of the second dielectric
structure 160 is selected to have a refractive index smaller than
that of each of the convex dielectric lenses 140. In some
embodiments, the second dielectric structure 160 at least partially
covers the convex dielectric lenses 140.
[0020] The color filters 1701R/170G/170B are formed on the second
dielectric structure 160 and respectively in the pixel regions
100R/100G/100B. The color filters 170R/170G/170B filter the
incident light to thereby obtain red, green and blue lights,
respectively. For illustration, the color filters 170R/170G/170B
include a dyed or pigmented material such as polymer, or other
suitable material.
[0021] The micro-lenses 180 are formed on the color filters
170R/170G/170B and in the pixel regions 100R/100G/100B
respectively. The micro-lenses 180 focus the incident light onto
the photo sensitive elements 120R/120G/120B. For illustration, the
micro-lenses 180 are formed of any material that may be patterned
and formed into lenses with high transmittance, such as acrylic
polymer and other suitable material.
[0022] Referring to FIGS. 2A-2B, FIGS. 2A-2B illustrate enlarged
partial views of the image sensor device 100 shown in FIG. 1 in
accordance with various embodiments. Each of the convex dielectric
lenses 140 has a width W and a height H. As shown in FIG. 2A, the
width W of the convex dielectric lens 140 is substantially
identical to a distance D between two opposite sides of the grid
150, and the height H of the convex dielectric lens 140 is
substantially identical to a thickness T of the second dielectric
layer 134. Alternatively, the height H of the convex dielectric
lens 140 may be smaller than the thickness T of the second
dielectric layer 134. In such cases, the convex dielectric lens 140
is entirely in the second dielectric layer 134. In some
embodiments, as shown in FIG. 2B, the height H of the convex
dielectric lens 140 is greater than the thickness T, such that a
portion 142 of the convex dielectric lens 140 is in the second
dielectric layer 134. The height H of the convex dielectric lens
140 may vary in accordance with the refractive indexes of the
convex dielectric lens 140, the first dielectric layer 132 and the
second dielectric structure 160. Further, in certain embodiments,
the width W of the convex dielectric lens 140 may be greater than
the distance D.
[0023] Referring to FIGS. 3A-3H, FIGS. 3A-3H illustrate
cross-sectional diagrams for fabricating an image sensor device 300
in accordance with some embodiments of the present disclosure. In
FIG. 3A, a substrate 310, photo sensitive elements 320R/320G/320B
and pixel circuits 322R/322G/322B are provided. The substrate 310
is a semiconductor substrate, which includes, but not limited to, a
semiconductor wafer, a silicon-on-insulator (SOI) substrate or an
epitaxial substrate. In some embodiments, the substrate 310 further
includes an elementary semiconductor, a compound semiconductor or
an alloy semiconductor. The photo sensitive elements 320R/320G/320B
are formed on the front side 310A of the substrate 310 and in the
pixel regions 300R/300G/300B respectively. In some embodiments, the
photo sensitive elements 320R/320G/320B are formed by a diffusion
process or an ion implantation process. For illustration, if the
photo sensitive elements 320R/320G/320B are PNP-type photodiodes
formed by the ion implantation process, the photo sensitive
elements 320R/320G/320B includes P-type pinned layers formed on
N-type doped regions, and the substrate 310 is a P-type
semiconductor substrate, in which the N-type doped regions are
formed on the substrate 310. In addition, the pixel circuits
322R/322G/322B are formed on the front side 310A of the substrate
310 and adjacent the photo sensitive elements 320R/320G/320B
respectively.
[0024] In FIG. 3B, a first dielectric layer 332 is formed on the
back side 310B of the substrate 310 opposite to the front site
310A. For illustration, the first dielectric layer 332 is formed by
a deposition process such as chemical vapor deposition (CVD),
physical vapor deposition (PVD), atomic layer deposition (ALD),
combinations thereof, or the like.
[0025] In FIG. 3C, a second dielectric layer 334 is formed on the
first dielectric layer 332. For illustration, the second dielectric
layer 334 is formed by a deposition process such as CVD, PVD, ALD,
combinations thereof, or the like. The first dielectric layer 332
and the second dielectric layer 334 forms a first dielectric
structure 330. In some embodiments, the material of the first
dielectric layer 332 and the second dielectric layer 334 are
selected, such that the first dielectric layer 332 has a refractive
index greater than the second dielectric layer 334.
[0026] In FIG. 3D, an isolating layer 340 is formed on the second
dielectric layer 334. In some embodiments, the isolating layer 340
includes an insulating material such as silicon oxide, silicon
nitride, silicon oxynitride, combinations thereof, or the like. In
some embodiments, the isolating layer 340 includes a metal material
such as aluminum, copper, or the like, a metal alloy material such
as aluminum alloy, copper alloy, or the like, a metal nitride such
as titanium nitride, tantalum nitride, or other suitable material.
For illustration, the isolating layer 340 is formed by a deposition
process such as CVD, PVD, or any suitable process.
[0027] In FIG. 3E, a grid 342 and recesses 344R/344G/344B are
formed by an etching process. The recesses 344R/344G/344B are
formed by removing parts of the isolating layer 340 and the second
dielectric layer 334. For illustration, the etching process
includes dry etching, wet etching, drilling, combinations thereof,
or the like. Bottoms of the recesses 344R/344G/344G directly adjoin
the first dielectric layer 332. The grid 342 is also formed for
separating the pixel regions 300R/300G/300B after the etching
process is done.
[0028] In FIG. 3F, convex dielectric lenses 350 are formed in the
recesses 344R/344G/344B and directly on the first dielectric layer
332. The convex dielectric lenses 350 are formed by a deposition
process such as CVD, PVD, or the like. In each of the pixel regions
300R/300G/300B, the convex dielectric lens 350 is formed to have a
convex side 350A oriented opposite to one of the photo sensitive
elements 320R/320G/320B and a planar side 350B oriented toward one
of the photo sensitive elements 320R/320G/320B. The material of the
convex dielectric lenses 350 is selected to have a refractive index
smaller than that of the first dielectric layer 332. In some
embodiments, the refractive index of each of the convex dielectric
lenses 350 is smaller than the second dielectric layer 334.
[0029] In the pixel regions 300R/300G/300B, the width and height of
the convex dielectric lenses 350, the thickness of the second
dielectric layer 334 and the width of the recesses 344R/344G/344G
(i.e. the distance between two opposite sides of the grid 342) are
adjustable in accordance with various embodiments. In some
embodiments, the width of each of the convex dielectric lenses 350
is substantially equal to or greater than the width of each of the
recesses 344R/344G/344G. In some embodiments, the height of each of
the convex dielectric lenses 350 is substantially equal to or
greater than the thickness of the second dielectric layer 334.
[0030] In FIG. 3G, a second dielectric structure 360 is formed on
the first dielectric structure 330, the convex dielectric lenses
350 and the grid 342. The second dielectric structure 360 is formed
to fill in the recesses 344R/344G/344B. For illustration, the
second dielectric structure 360 is formed by a deposition process
such as CVD, PVD, ALD, combinations thereof, or the like. The
material of the second dielectric structure 360 is selected to have
a refractive index smaller than that of each of the convex
dielectric lenses 350. In some embodiments, the second dielectric
structure 360 at least partially covers the convex dielectric
lenses 350.
[0031] In FIG. 3H, color filters 370R/370G/370B are formed on the
second dielectric structure 360. For illustration, the color
filters 370R/370G/370B are selectively patterned and sequentially
formed by an exposure and development process using a
photo-mask.
[0032] Further, in FIG. 3H, micro-lenses 380 are respectively
formed on the color filters 370R/370G/370B. For illustration, the
micro-lenses 380 are formed using a material in a liquid state by a
spin-on technique. Such method is performed to produce a
substantially planar surface and micro-lenses 380 with a
substantially uniform thickness. In some embodiments, other
methods, such as CVD, PVD, and/or the like, are also performed for
forming the micro-lenses 380.
[0033] Referring to FIG. 4 with FIGS. 3A-3H, FIG. 4 is a flow chart
of a method 400 for fabricating an image sensor device in
accordance with some embodiments. The method 400 begins at
operation 402, where a substrate 310 is provided, as shown in FIG.
3A. At operation 404, a photo sensitive element 320R/320G/320B is
formed on a front side 310A of the substrate 310 for receiving
incident light transmitted through the substrate 310. At operation
406, a pixel circuit 322R/322G/322B is formed on the front side
310A of the substrate 310 for electrical interconnection with the
photo sensitive element 320R/320G/320B. At operation 408, a first
dielectric structure 330 is formed on the back side 310B of the
substrate 310. In some embodiments, the first dielectric structure
330 includes a first dielectric layer 332 formed on the back side
310B and a second dielectric layer 334 formed on the first
dielectric layer 332, as shown in FIGS. 3B-3C. At operation 410, an
insulating layer 340 is formed on the first dielectric structure
330, as shown in FIG. 3D. At operation 412, a grid 342 and a recess
344R/344G/344B are formed by performing an etching process to
remove parts of the isolating layer 340 and a portion of the first
dielectric structure 330, as shown in FIG. 3E. At operation 414, a
convex dielectric lens 350 is formed in the recess 344R/344G/344B,
as shown in FIG. 3F. At operation 416, a second dielectric
structure 360 is formed on the first dielectric structure 330, the
convex dielectric lens 350 and the grid 344, as shown in FIG. 3G.
At operation 418, a color filter 370R/370G/370B is formed on the
second dielectric structure 360, and a micro-lens 380 is formed on
the color filter 370R/370G/370B, as shown in FIG. 3H.
[0034] In accordance with the embodiments of the present
disclosure, an additional convex dielectric lens is formed between
a color filter and a substrate in each pixel region of an image
sensor device, and the convex dielectric lens has a refractive
index greater than that of a dielectric structure on a convex side
of the convex dielectric lens. Thus, incident light is condensed
into a photo sensitive element in a more effective manner, such
that the quantum efficiency of the image sensor device is improved.
In addition, since the crosstalk issue is avoided, the SNR of the
image sensor device increases.
[0035] It is noted that, the aforementioned convex dielectric
lenses in the present disclosure may be replaced with concave
dielectric lenses in accordance with various embodiments. For
example, a concave dielectric lens may be formed in replace of the
aforementioned convex dielectric lens in each pixel region to have
a planar side oriented toward incident light and a concave side
oriented toward the photo sensitive element, and the concave
dielectric lens has a refractive index greater than that of the
aforementioned second dielectric structure and smaller than that of
the aforementioned first dielectric layer. Further, in some
embodiments, the first dielectric structure is a single layer
structure, and the convex dielectric lenses directly adjoin the
back side of the substrate.
[0036] In accordance with some embodiments, an image sensor device
includes a semiconductor device, a plurality of photo sensitive
regions, a dielectric layer, a grid structure, and a plurality of
convex dielectric lenses. The plurality of photo sensitive regions
are in the semiconductor substrate. The dielectric layer is on a
backside surface of the semiconductor substrate facing away from
the plurality of photo sensitive regions. The grid structure is on
a backside surface of the dielectric layer facing away from the
semiconductor substrate. The grid structure includes a plurality of
grid lines spaced from each other. The plurality of convex
dielectric lenses are alternately arranged with the plurality of
grid lines of the grid structure on the backside surface of the
dielectric layer. Apexes of the plurality of convex dielectric
lenses are lower than top ends of the plurality of grid lines of
the grid structure.
[0037] In accordance with some embodiments, an image sensor device
includes a semiconductor substrate, a plurality of photo sensitive
regions, a first dielectric layer, a plurality of convex dielectric
lenses, a dielectric structure, a layer of color filters, and a
plurality of micro-lenses. The plurality of photo sensitive regions
are in the semiconductor substrate. The first dielectric layer is
on a backside surface of the semiconductor substrate facing away
from the plurality of photo sensitive regions. The plurality of
convex dielectric lenses are on a backside surface of the first
dielectric layer facing away from the semiconductor substrate. The
dielectric structure is over convex sides of the plurality of
convex dielectric lenses. The layer of color filters is on a
backside surface of the dielectric structure facing away from the
plurality of convex dielectric lenses. The plurality of
micro-lenses are on a backside surface of the layer of color
filters facing away from the dielectric structure. The plurality of
micro-lenses respectively overlap the plurality of convex
dielectric lenses, and each of the plurality of micro-lenses
laterally extends past opposite edges of a corresponding one of the
plurality of convex dielectric lenses.
[0038] In accordance with some embodiments, an image sensor device
includes a semiconductor substrate, a plurality of photo sensitive
regions, a layer of a first dielectric material, a plurality of
convex dielectric lenses, a lower grid structure, and an upper grid
structure. The plurality of photo sensitive regions are in the
semiconductor substrate. The layer of first dielectric material is
on a backside surface of the semiconductor substrate farthest from
the plurality of photo sensitive regions. The plurality of convex
dielectric lenses are on a backside surface of the layer of the
first dielectric material farthest from the semiconductor
substrate. The lower grid structure is on the backside surface of
the layer of the first dielectric material. The lower grid
structure includes a plurality of lower grid lines alternately
arranged with the plurality of convex dielectric lenses from a
cross-sectional view. The plurality of lower grid lines are formed
of a second dielectric material having a lower refractive index
than the first dielectric material. The upper grid structure has a
plurality of upper grid lines respectively over the plurality of
lower grid lines of the lower grid structure from the
cross-sectional view.
[0039] Although the present embodiments and their advantages have
been described in detail, it should be understood that various
changes, substitutions and alterations can be made herein without
departing from the spirit and scope of the disclosure as defined by
the appended claims.
[0040] Moreover, the scope of the present application is not
intended to be limited to the particular embodiments of the
process, machine, manufacture, composition of matter, means,
methods and steps described in the specification. As one of
ordinary skill in the art will readily appreciate from the
disclosure, processes, machines, manufacture, compositions of
matter, means, methods, or steps, presently existing or later to be
developed, that perform substantially the same function or achieve
substantially the same result as the corresponding embodiments
described herein may be utilized according to the present
disclosure. Accordingly, the appended claims are intended to
include within their scope such processes, machines, manufacture,
compositions of matter, means, methods, or steps.
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